The Modification Of Tio <sub> 2 </ Sub> Photocatalytic Degradation Studies Of Diphenyl Ether Pesticides

In this thesis, we study of the experiments of the photocatalytic degradation of Acifluorfen were carried out using Cu-TiO2 and Sn-TiO2-x as photocatalysts. Our objective was to explore the effects of the irradiation intensity, the catalyst dosage, the pH values, the type and the amount of anions and cations often used in agriculture, and the different initial concentration on the degradation of Acifluorfen. And we studied of photocatalyst kinetic of Acifluorfen under different conditions. This results also suggest that photodegradation passway of Acifluorfen via identify of the intermediate produce.The experimental results indicate that:The smaller activities found at acidic and basic pH are explained by considering the ionisation state of Acifluorfen and the charge density of TiO2; Effect of the anions addition on the degradation of Acifluorfen is remarkable for the reaction system using Cu-TiO2 as photocatalyst, but there is less effect for Sn-TiO2-x; The influence of metal ions like K+ and Ca2+ on the photocatalytic efficiency of TiO2 in the elimination of Acifluorfen is unnoticeable, but a detrimental effect of the presence of Cu2+ is observed. In addition, the experiment of active specie of two catalytics in the photoreaction, the results indicate that·OH is the main active specie for Cu-TiO2, and the amount of the active oxygen species in the reaction system using Sn-TiO2-x as photocatalyst are more than that of Cu-TiO2, there are according with the former research of the modificational mechanism of the TiO2.Finally, the results of photocatalytic experiment reveal that the decline of Acifluorfen concentration in the solution followed a zero-order kinetics. And, the research of the intermediate products indicated that photodegradation of Acifluorfen proceeds via a number of decarboxylation and cleavage of ether linkage. The last, they'll minerazation for CO2 and H2O.